Method and apparatus for heat sealing seat cushion covers



June 24, 1969 J. H. WOODARD 3,451,075

METHOD AND APPARATUS FOR HEAT SEALING SEAT CUSHION COVERS Filed Aug. 30, 1967 Sheet 1 0f 2 Y 4 WTFORNEYS June 24, 1969 J. H. w oDARb METHOD AND APPARATUS FOR HEAT SEALING SEAT CUSHION COVERS Filed Aug. 30, 1967 fl w P/PESSUAPE fiA/D INVENTOR.

5 012 1%. ifaoda'rci M MTORNEYS United States Patent US. Cl. 5.-360 Claims ABSTRACT OF THE DISCLOSURE The invention is directed to a method and apparatus of forming seat cushion covers by heat-sealably securing the panels of heat-scalable material together at the peripheral surfaces thereof while simultaneously forming a welt between the panels of material. The seat cushion cover has a folded over portion which is wrapped about a flexible cord to form the welt, and the folded over portion is sewn together to confine the welt in position. The folded over portion is then heat-sealably secured to another panel of heat-scalable material forming the seat cushion. The apparatus used to form the seat cushion cover includes a base plate for receiving a fiat panel of material which forms the top of the seat cushion and a four-sided container having open opposite ends. A plurality of resilient finger tabs are secured to the four-sided container and have a gripping portion to engage the material placed therein and hold the material in contact with a heat transfer edge of the container. The four-sided container includes a plurality of bosses which engage releasable clamp means secured to the base plate for securably positioning the container in position over the flat piece of material. Spring clips may be provided within the interior of the container to hold the material placed therein in an upright position against the interior walls thereof during the heat sealing operation.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to seat cushions, and more particularly to seat cushion covers constructed of heat-sealable vinyl material to form the outer casing of the seat cushion. Specifically, the present invention is directed to a method and apparatus of heat-sealably securing panels of vinyl-coated cloth material together at the peripheral portions thereof while simultaneously forming and sealing a welt at the edge defining the top and side walls of the cushion cover. The seat cushion cover constructed in accordance with the principles of this invention has particular utility when used for outdoor furniture as the cover prevents the resilient fiber material within the seat cushion from becoming wet due to rain or the like.

Description of the prior art Heretofore, seat cushion covers for outdoor furniture have been constructed of vinyl-coated cloth and sewn together to form the various shapes of the seat cushions of lawn chairs and the like. However, despite the use of waterproof material to construct the seat cushion covers, moisture still enters the interior of the seat cushion through the holes formed by the stitching operation when the panels of the seat cushions are sewn together. The holes formed by the stitching of the panels, although large enough to allow water to pass into the cushion are relatively small therefore requiring a long period of time for the interior of the cushion to dry out, and in some cases requiring the seat cushion cover to be removed to allow the foam rubber resilient pad therein to be dried. Additionally, to form a welt along the peripheral edges of the side and top panels of the seat cushion required the welt to be sewn in position.

SUMMARY OF THE INVENTION Therefore, one of the objects of the present invention is to provide a seat cushion cover which is totally waterproof thereby eliminating the possibility of moisture from entering the interior of the seat cushion.

Another object of the present invention is to provide a seat cushion cover which includes a bead or welt formed between the top panel and side wall panels thereof and wherein the stitching used to form the welt are sealed by molten plastic material during the heat sealing operation.

Still another object of the present invention is to provide a seat cushion cover wherein one end of the side wall panel thereof is heat-sealably secured to the top panel and the other end thereof is provided with an extruded U- shaped plastic member which is used to engage a frame member of the seat cushion thereby securing the resilient pad and the cover to the frame member.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective View of a seat cushion constructed in accordance with the principles of this invention;

FIGURE 2 is a cross section of the seat cushion of FIG- URE 1 taken along the lines II-II and shows the detailed construction of the seat cushion cover;

FIGURE 3 is a perspective view of the apparatus used to form the seat cushion cover shown in FIGURES 1 and 2;

FIGURE 4 is an enlarged elevational sectional view showing the cooperation of the various components of the apparatus shown in FIGURE 3 while forming the seat cushion;

FIGURE 5 is a schematic representation of the apparatus used to construct the seat cushion of the present invention and shows the pressure and heat source associated therewith; and

FIGURE 6 is a cross sectional elevational view of an alternate arrangement of a seat cushion cover constructed in accordance with the principles of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Seen in FIGURE 1 is a seat cushion 10 which is constructed in accordance with the principles of this invention. The seat cushion 10 includes a cover 11 which is positioned about a resilient interior member, such as foam rubber or the like. The cover 11 includes a top panel 12 of flexible resilient material such as vinyl-coated cloth. The top panel 12 is secured to a side wall panel 13, which is of the same material, by heat sealing. A bead or welt is formed at the periphery of the top and side panels 12 and 13 to form an edge therebetween.

A bottom panel is secured to the side wall panel 13 opposite the top panel 12 by heat sealing and a welt 16 is formed between the side panel 13 and the bottom panel. Additionally, a zipper (not shown) may be included in the side wall panel 13 to allow a resilient filler member such as a foam rubber cushion to be inserted into the seat cushion 11. It will be understood that the resilient filler member has substantially the same shape as that of the seat cushion cover.

Seen in FIGURE 2 is the detailed construction of the seat cushion cover 11 as it confines a resilient cushion member 17. The welts 14 and 16 are formed on the side panel 13 in the same manner and the side panel is secured to the top and bottom panels 12 and 15 in the same manner. Therefore only a discussion of the side panel and welt 14 engaging the top panel 12 will be given.

The side panel 13 includes a folded over portion 18 which extends a short distance towards the welt 16 and a folded back portion 19. The material of the side wall 13 then extends towards a cord 20 and folded over and wrapped about the cord to form the welt 14. Stitches, indicated by reference numeral 21 may be provided to maintain the cord 20 in position to facilitate heat-sealably securing the top panel 12 to the side panel 13.

The material of the side panel 13 extends from the cord 20 to form a tab 22. The top panel 12 includes a downwardly extending portion 23 which is in engagement with the tab 22 and heat-sealably secured thereto.

A heat sealed joint 26 is formed between the downward extended portion 23 and the tab 22, and a heat sealed joint 27 is formed between the folded over portion 18 and the folded back portion 19. It will be noted that the heat sealed joints are formed over the stitches 21 to eliminate any possibility of moisture from entering through the holes formed by the stitches.

The apparatus used to form the seat cushion cover of the present invention is shown in FIGURE 3. The apparatus includes a base plate 30 which is mounted on a table 31 for receiving, for example, the top panel 12 in a flat position. The excess material indicated by reference numeral 12a of the top panel 12 may be trimmed after assembly.

A four-sided container indicated generally by reference numeral 32 receives the side wall panel 13 at the interior thereof. The tab 22 of the side wall panel extends from under the container and is ripped by a plurality of resilient finger members 33. Each of the resilient finger members 33 includes a release hook 34 which may be pulled to urge the member 33 away from the container so that the tab 22 may be placed between the outer surface of the container and the retaining point of the finger.

A plurality of spring clips 36 may be provided at the interior of the container at the upper edge thereof opposite the edge receiving the tab 22. The spring clips provide means for holding the resilient side wall member in position while the heat sealing operation is performed.

A pair of bosses 37 and 38 are formed on the container 22 and extend outwardly therefrom to be engageable by a corresponding pair of releasable clamps 39 and 40. The releasable clamps 39 and 40 are secured to the table 31 and provide means for holding the container 32 in position prior to the heat sealing operation.

For a better understanding of the novel features of the apparatus of the present invention, reference is now made to FIGURE 4 which is an enlarged elevational sectional view of the apparatus of FIGURE 3 showing the cooperation between the base plate 30 and the container 32 while forming a seat cushion cover. The side panel 13 is placed in the container with the finished vinyl side facing radially inwardly as indicated by reference numeral 13a. The welt 14 is positioned adjacent the edge of the container and the tab 22 and the folded over portion 18 and folded back portion 19 are positioned under the heat transfer edge 32a of the container. It will be understood that the container 32 and the base plate 30 are formed of a material to allow radial frequency heating to take place between the container and the base plate. For example, the container 32 and base plate 30 may be constructed of aluminum.

The edge of the folded back portion 19 extends slightly beyond the outer surface of the side walls of the container and is held in position by the pointed end 33a of the resilient finger members 33. Therefore, after the side wall member 13 is in position within the interior of the container 32 the container and the side wall member are placed over the top panel 12 which has its finished surface extend upwardly toward the container.

After the container and side wall 13 are placed over the top panel 12 pressure is applied to the container 32 by a pressure and heat source 36, shown in FIGURE 5. The heat source comprises a conventional radial frequency heater device which transfers the heat through the container 32 to the dielectric junction formed by the top and side panels 12 and 13. Energization of the heat source causes dielectric heating at the heat transfer edge 32a to form the heat sealed joints 36 and 37 over the stitches 21.

FIGURE 6 shows an alternate arrangement of a seat cushion cover constructed in accordance with the principles of this invention and includes a U-shaped channel 37 which is sewn to the peripheral portion of the side panel 13 opposite the welt 14. The U-shaped channel 37 fits around a metal frame member 38. The extruded U-shaped member 37 may be sewn or heat-sealably secured to the side wall panel 13 or it may be sewn and heat-sealably secured to prevent moisture from passing through the holes formed by the stitches.

The foam rubber filler pad 17 is held in position on the frame by placing the cover 11 over the pad and the frame and slipping the U-shaped member 37 over the edge of the frame to secure the pad and the cushion cover thereto.

Accordingly, the present invention has provided a seat cushion cover which may be constructed of waterproof vinyl-coated material and in addition is waterproof at the seams thereof to eliminate moisture from passing through holes which may be caused by stitching. Additionally, it will be understood that the seat cushion cover includes a welt formed between the top and side panels thereof. Also, the present invention has provided apparatus for confining and aligning the side wall panel including a welt formed thereon prior to the heat sealing operation.

It will be understood that variations and modifications may be effected without departing from the spirit and scope of the novel concepts of this invention.

I claim as my invention:

1. A seat cushion cover comprising:

a first panel of flexible heat-scalable material;

a flexible cord, said first panel having a peripheral portion thereof folded over and wrapped about said cord to form a welt;

a second panel of flexible heat-scalable material having a peripheral portion thereof adjacent said welt; and

a heat sealed joint formed between said peripheral portion of said second panel and the folded over portion of said first panel, thereby securing said cord in position on said first panel and securing said first and second panels together.

2. A seat cushion cover according to claim 1 further including a folded back portion formed on said first panel adjacent said welt and opposite said second panel; and stitches passing through said folded back portion and said folded over portion to hold said cord to said first panel.

3. A seat cushion cover according to claim 2 wherein said heat sealed joint is formed over said stitches.

4. A seat cushion cover according to claim 2 wherein said folded over portion extends from said cord to form a tab, and wherein said heat sealed joint is formed between said tab and said second panel.

5. A seat cushion cover according to claim 1 wherein said first panel forms the side walls of said seat cushion and said second panel forms the top of said seat cushion, said welt defining an edge between said side walls and said top and further including a second flexible cord; said first panel having the other peripheral portion thereof folded over and wrapped about said second cord to form a second welt; a third panel of flexible heat-scalable material forming the bottom of said seat cushion cover, said bottom having a peripheral portion thereof adjacent said second welt; and a second heat-scalable joint formed between said other peripheral portion of said first panel and said third panel, thereby securing said second cord in position on said first panel and securing said first and third panels together.

6. A seat cushion cover according to claim 5 wherein the other peripheral portion of said first panel includes a folded back portion formed adjacent said welt and opposite said third panel; and stitches passing through said folded back portion of said other peripheral portion to hold said second cord to said first panel.

7. A seat cushion cover according to claim 6 wherein said second heat seal joint is formed over the stitches at the other peripheral portion of said first panel.

8. A seat cushion cover according to claim 6 wherein said folded over portion of said other peripheral portion of said first panel extends from said second cord to form a second tab, and wherein said second heat sealed joint is formed between said tab and said third panel.

9. A seat cushion cover according to claim 1 wherein said second panel forms the top of the seat cushion cover and said second panel forms the side walls thereof, and further including a U-shaped member sewn to the other peripheral portion of said first panel opposite said welt.

10. A seat cushion cover according to claim 2 wherein said second panel forms the top of the seat cushion cover and said second panel forms the side walls thereof, and further including a U-shaped member sewn to the other peripheral portion of said first panel opposite said welt.

References Cited CASMIR A. NUNBERG, Primary Examiner.

US. Cl. X.R. 

